The NRC says Dr. Gary Kao cannot take part in agency-related activities without undergoing more training. A medical physicist was also sanctioned Wednesday.

The commission found Kao took part in 91 procedures in which veterans received incorrect doses from radioactive seeds implanted in the prostate to kill cancer cells. It found many of Kao's patients received insufficient doses because he implanted seeds in nearby organs or surrounding tissue.

Kao told a Senate panel in 2009 that he acted in patients' best interest. A phone message left for Kao's lawyer was not immediately returned.